Great excercise to work the latissimus dorsi or back muscles are Chin Ups which can be done in home training using a chin up bar, out door training or in the gym using a frame or smith machine. Using different grip alternatives utilises different parts of the of the same muscle. Wide grip focuses more on using the back muscles with less assistance from the arms. Whereas narrow grip allows for more assistance with the arms but does work different key areas on the latissimus dorsi.